Ingrown and entrenched meanders are both examples of incised meanders. These are a meanders that have cut down deeply into the landscape when a river’s base level drops. This causes the river to gain a lot of vertical erosion power and thus they erode vertically.
Ingrown meanders occur when this incision of the river is slow and thus lateral erosion also occurs. This creates an asymmetrical cross-valley shape.
Entrenched meanders have a symmetrical cross section as a result of rapid incision into the bedrock; vertical erosion dominates and thus the valley has a steep gorge-like appearance.
These adjustments by the river to the new base level is known as river rejuvenation as the river attempts to restore its long profile.
Hope that helps!